\usepackage{geometry}
\geometry{papersize={5in,8in},margin=0.75in}
\usepackage{graphicx}
\makeatletter
\let\oldincludegraphics\includegraphics
\renewcommand{\includegraphics}[2][]{\begin{center}\oldincludegraphics[#1]{#2}\end{center}}
\makeatother
\usepackage{fancyhdr}
\pagestyle{fancy}
\fancyhf{}
\renewcommand{\headrulewidth}{0pt}
\fancyhead[C]{\leftmark}
\fancyfoot[C]{\thepage}
\usepackage{etoolbox}
\raggedbottom
\usepackage{titlesec}
\titlespacing*{\section}{0pt}{0.5in}{20pt}
\usepackage{fontspec}
\setmainfont{Open Sans}
\setlength{\spaceskip}{0.33em plus 0.12em minus 0.08em}
\xspaceskip=\spaceskip
\hyphenpenalty 10000
\exhyphenpenalty 10000
\clubpenalties 2 10000 10000
\widowpenalties 2 10000 10000
% Prevent blank pages inserted to start chapters on odd pages
\let\cleardoublepage\clearpage